Study On Cold Resistance Of Sichuan Wild Centipedegrass

In the subtropical areas, the popularization and apply of centipedegrass is limited due to relatively weak cold resistance and relatively long withered time in winter. In the experiment, the thirteen wild centipedegrass accessions collected from Sichuan were selected as experimental materials. We studied the change of activities of SOD and POD, contents of MDA, chlorophyll a and chlorophyll b from September to December, and withered days of every centipedegrass accession in 2003. Moreover, the thirteen wild centipedegrass accessions were cultivated in pot and were used in cold hardening. All the centipedegrass accessions in pot were exposed to 8 hours of light at 23C and 16 hours of dark at 4C every day, except a pot of every centipedegrass accession. The processed days were designed to 4, 6, 8, 12 days. We studied the change of activities of SOD and POD, content of MDA, electrolytic permeability and winter withered days after cold hardening. The result showed:1. Along with the drop of natural temperature from September to December in 2003, namely the temperature descended from 20C to 7C, activities of SOD and POD, contents of MDA and chlorophyll ascended gradually in all the centipedegrass accessions. Contents of Chl and Chla descended gradually in all the centipedegrass accessions. But content of Chlb ascended gradually in all the centipedegrass accessions.2. In the last ten-day period of December, namely the lowest temperature was 5X2, the thirteen wild centipedegrass accessions withered in succession, the withered days of DJ01 were 55 days, and the withered days of QL01 and XJ01 were 75 days. The remainder of them was 20 days.3. According to foregoing analysis, we gained that some cold-resistance physiological reaction of centipedegrass. In the temperature descended from 20C to 7C, activities ofSOD and POD increased in body of centipedegtass, so lightened the injure of cell membrane due to active oxygen metabolism, and reduced the generation of MDA. At the same time because the content of Chlb ascened, lightened the injure of content Chla due to low temperature. In the lowest temperature descended to 5C, the foregoing physiological reaction were destroyed, so the centipedegrass withered.4. These physiological quotas were regarded as the indexes of correlation analysis. The correlation analysis indicated that activities increasing average value of SOD and POD, content increasing average value of MDA were the best physiological quotas that appraise cold-resistance of centipedegrass.5. Activities increasing average value of SOD and POD, contents increasing average value of MDA and Chlb, content decreasing average value of Chla, and winter withered days were regarded as the indexes of cluster analysis. The analysis indicated that cold resistance of DJ02, DJ01, YB01, YA02 were superior, cold resistance of MS09, MS04, LS01, EM02, LC01 were secondary, and cold resistance of EM01, LS02, XJ01, QL01 were inferior.6. At the same low temperature of cold hardening, the hardening time that every centipedegrass needed was different. After cold hardening, cold-resistance of 13 centipedegrass accession was improved.